How to override Filmic color space in the Compositor nodes?
Using filmic blender requires you to use much brighter values on your lights, as it is designed to work with a much wider dynamic range. To understand how it works read the following link carefully: Render with a wider dynamic range in cycles to produce photorealistic looking images . 

Also you need to explore the different look transforms in the color management section to set the contrast to your liking. Read: https://github.com/sobotka/filmic-blender. 

You can use the false colour look to evaluate the values within the image.

Lastly, you should try using the ASC-CDL node to make adjustments. Read: What is the the ASC-CDL node?